1. Field of the Invention
The present invention relates to a vehicular lamp used in a vehicle.
2. Description of the Related Art
Conventionally, a vehicular lamp that uses a filament bulb as a light source is known. In this type of lamp, breaking of the light source was detected by measuring impedance of the lamp, for example. Moreover, a breaking detection device for an automotive lamp is conventionally known that is used as a multiple light brake light and the like as disclosed, for example, in Japanese Patent Application Laid-Open No. 10-217851, pages 3-4, FIGS. 1-3.
However, in a case where a light-emitting diode is used as the light source, a lighting circuit having large impedance may be used because the light-emitting diode can emit light by a smaller current value as compared to the filament bulb. In this case, the impedance of the lamp is large even if the light source is not broken. Thus, according to the conventional technique, the braking of the light source was not detected appropriately in some cases.